Spreader stoker apparatus



July 30, 1%, W. KEssLER SPREADER STOKER APPARATUS Original Filed July25, 1943 INVENTOR WILBU R KESSLER ATTORNEY FIG 3.

FIG. 2. E

WITNESSES:

. MW, yfl Www Patented July 30, 1946 SPREADER STOKER APPARATUS WilburKessler, Newtown Square, Pa., assignor to Westinghouse ElectricCorporation, East Pittsburgh, Pa., a corporation of PennsylvaniaOriginal application July 23, 1943, Serial No.

495,807, now Patent No. 2,390,155, dated Decemher 4, 1945. Divided andthis application May 5, 1945, Serial No. 592,112

This invention relates to stokers, more particularly to stokers of thespreader or sprinkler type, andfhas for an object to provide improvedapparatus of this character.

To the best of applicants knowledge, most industrial spreader-feedstokers on the market fail to provide uniform distribution of fuellaterally of the grate surface. The bed of fuel deposited thereon isgenerally thin along the lateral edges of the area of distribution ofeach feeder unit; and, where a plurality of such units are employed in afurnace, the space on the grates between the feeders is nearly empty offuel adjacent the furnace front wall, this nearly empty area beingtriangular in shape with its base at the front wall and having analtitude longitudinally of the grate of from 2 to 3 feet.

Large quantities of excess air 'are admitted to the combustion chamberthrough the nearly empty spaces on the grates and the thin portions ofthe fuel bed at the lateral edges. 'As a result, either a high furnaceor a high degree of turbulence is necessary to make this excess airuseful for combustion.

Therefore, another object of the invention is to provide a spreader fuelfeeder for stokers which will provide more uniform lateral distributionof the fuel laterally of the furnace than has been obtainableheretofore.

A further object of the invention is the provision of a fuel-feedingmechanism for delivering a greater quantity of fuel to the end portionsof a fuel-impelling device, than is delivered to the intermediateportion thereof.

These and other objects are effected by the invention as will beapparent from the following description and claims taken in connectionwith the accompanying drawing, forming a part of this application, inwhich:

Fig. 1 is a plan view of a furnace fed by a pair of conventionalspreader units, and illustrating the problem which applicant is solving;

Fig. 2 is a plan view of a construction of the invention, taken alongthe line 11-11 of Fig. 4, looking in the direction indicated by thearrows;

Fig. 3 is a sectional View taken along the line IIIIII of Fig. 2,looking in the direction indicated by the arrows; and

Fig. 4 is a sectional view taken along the line IVIV of Fig. 2, lookingin the direction indicated by the arrows.

Referring now to the drawing more in detail, with particular referenceto Fig. 1, there is shown a furnace l0, comprising a front wall ll, sidewalls l2, and. a rear wall l3, the front wall ll 2 Claims. (Cl. 110-415)2 Y having a pair of openings [4 therein, through which fuel is fed bythe spreader units Hi to the grate structure 16 forming the bottom ofthe furnace combustion chamber. In this figure, the numeral l8 indicatesthe fuel bed as normally deposited upon the grate surface by theconventional industrial spreader stoker units now on the market. Thelateral areas of relatively thin fuel deposits are indicated by thereference character [9, while 26] indicates the portions of the gratesurface which are nearly empty of fuel and through which largequantities of excess air pass from the plenum chamber below the gratestructure to the combustion chamber thereabove.

In order to make up for the deficiency of fuel along the lateralportions of the fuel de-.

posits upon the grate surface, it is proposed to feed to the edge or endportions of the impellers of the spreader units, a greater quantity offuel per unit area of ram face than is delivered to the intermediateportions of the impellers, and Figs. 2, 3 and 4 illustrate one form ofapparatus for providing this additional supply of fuel.

Referring now more particularly to Figs. 2, 3 and 4, fuel is fed fromthe hopper 22 by rams 23 and 24 rearwardly over the spill plate 26 tothe rotary impeller 21 disposed therebeneath, the blades of the rotaryimpeller projecting the fuel fed thereto rearwardly through the furnacefront wall opening M to the grate 16 in the bottom of the furnace.

Reciprocatory motion is adapted to be imparted to the rams 23 and 24 ofeach spreader unit l5 by a single oscillating shaft 30, carryingcrankarms 3| and 32, the former being connected to the central ram 23 bylinks 33 and the crankarms 32 being connected to the side rams 24 bylinks 34.

As best shown in Fig. 4, the links 33, providing the driving connectionfor the central ram 23, include a lost-motion connection 36 between thelinks 33 and the crankarms 31, by which the stroke of the central ram 23may be varied by adjustment of the handwheel 31. Inasmuch as the links34 providing the driving connection for the side rams 24 are of fixedlength, it will be apparent that it is possible to vary the relativelengths of the feeding strokes of the rams 23 and 24. Inasmuch as thethree rams are driven from the common shaft 30, it will be apparentthat, if the central ram 23 has a shorter stroke.

than the side rams 24, the latter will deliver a greater quantity offuel to the corresponding side or end portions of the rotary impeller21, thereby providing excess fuel at these locations tending to minimizethinness of fuel bed at the edges of the areas fed by the spreaderunits.

This application is a division of my copendin application Serial No.495,807, filed July 23, 1943, now Patent No.;2,390,155, granted December4, 1945. t

While the invention has been shown in but one form, it will be obviousto those skilled in the art that it is not so limited, but issusceptible of various changes and modifications without departing fromthe spirit thereof.

What is claimed is:

1. In a stoker, fuel-feeding mechanism comprising a hopper; an impeller;areciprocal ram structure for pushing fuel from the hopper to theimpeller, said ram structure comprising an' intermediate ram and an endram at each side of said intermediate ram; means for impartingreciprocatory motion to the intermediate ram to cause it to deliver fuelto the corresponding intermediate portion of the impeller at apredetermined rate; and means for imparting reciprocatory motion to theend rams to cause them to deliver fuel to the correspondinglend portionsof the impeller, said last-mentioned means providing a longer workingstroke of the end rams than of the intermediate ram, whereby said endrams deliver more fuel per unit area of ram face than does saidintermediate ram.

. 2. In a stoker, fuelfeeding mechanism comprising a hopper; animpeller; a reciprocal ram structure having an effective widthtransverse to the direction of its reciprocation substantially equal tothe length of the impeller in the same direction, said ram structurecomprising a spaced pair of end rams and one or more intermediate ramstherebetween; means for imparting reciprocatory motion to theintermediate ram or rams to cause them to push fuel from the hopper tothe intermediate portion of the impeller; and means for impartingreciprocatory motion to the end rams to cause them to push fuel from thehopper to the corresponding end portions of the impeller, saidlast-mentionedmeans providing a longer working stroke of the end ramswhereby said end rams deliver more fuel per unit area of ram face to thecorresponding end portions of the impeller than the intermediate ram orrams deliver to the intermediate portion of the impeller.

" WILBUR KESSLER;

